When forming compound nouns featuring more than one 'initial' noun, I seem to remember that there is a way to use a hyphen with one or both of those initial nouns to avoid having to repeat the second noun in the compound, but I'm not sure exactly how this works. Could someone help me with this, please?
What I want to avoid (repeating 'trees'):
'Drawing up problem trees and solution trees...'
What I believe may be correct but am not sure about:
A. 'Drawing up problem- and solution trees...'
Or is it:
B. 'Drawing up problem- and solution- trees...'